Page "To Say Nothing of the Dog" Paragraph 37

In the later chapters this manifests itself as unexpected trips to times such as 2018 ( in an earlier version of the time travel lab ), 1933 ( where an enlightening conversation about the mysteries of Agatha Christie is overheard ) and to 1395 ( where Ned notices a resemblance between Mary Botoner and someone he knows in 2057 ).

Finally both Ned and Verity find themselves in Coventry Cathedral on the night of its destruction, the very place and time that nobody has been able to reach before.

They are there to witness something, but what?